The Temperature at which Manure Becomes Compost.
Posted by garth on 06 May 2009 at 04:34 pm | Tagged as: compost, dropstone farms, paperwork, washington
This is not legal advice, please consult your county extension. That’s what they’re there for.
I like compost, soil likes compost, worms like compost. Everyone likes compost. You know what I don’t like? Pathogens. Pathogens and weed seeds that show up in uncomposted manure. At last year’s Tilth Producers conference I attended a workshop on static aerated composting given by Scott and Amy Turner of Blue Dog Farm. (Actually, I’m not positive it was both of them presenting because that’s not in my notes)
At any rate, there are rules governing the spreading of manure on Organic farms that specify a certain window prior to harvest (90-120 days, depending) but, once you’ve composted manure, it is no longer manure, it’s compost. However, I could not find a reliable source* for when manure counts as compost. And it was a tricky research problem especially for someone who doesn’t read legal writing particularly well. The Wisconsin State DNR links to the s. NR 502.04, Wis. Adm. Code [PDF 194KB] Compost Performance Standards which includes the following paragraph alluding to a national standard:
(h) Materials resulting from composting shall be:
1. Stabilized to eliminate pathogenic organisms and to ensure that the materials do not reheat upon standing.
2. Free of sharp particles which could cause injury to persons handling the material.
3. Free of toxins which could cause detrimental impacts to public health or the environment.
Note: Pathogens are defined in ch. NR 204 as “disease causing organisms, including but not limited to certain bacteria, protozoa, viruses and viable helminth ova.”
Appropriate methods for pathogen elimination during composting are specified in 40 CFR, Part 257, Appendix II, Section B:
1. For in−vessel or static aerated pile composting, maintain a continuous minimum temperature of 55° C, or 131°F, for a minimum of 3 consecutive days.
2. For windrow composting, attain a minimum temperature of 55°C, or 131°F, on a minimum of 15 days, which are not required to be consecutive, and turn the windrow a minimum of 5 times during the high temperature periods.
The document referenced at the state level is40 CFR : Protection of the Environment, a monstrous collection of regulations that the EPA has thoughtfully put online (Good jobs, folks!). The section relevant to reducing pathogens in compost states the following:
Composting: Using the within-vessel composting method, the solid waste is maintained at operating conditions of 55 °C or greater for three days. Using the static aerated pile composting method, the solid waste is maintained at operating conditions of 55 °C or greater for three days. Using the windrow composting method, the solid waste attains a temperature of 55 °C or greater for at least 15 days during the composting period. Also, during the high temperature period, there will be a minimum of five turnings of the windrow.
So, as I read the codes, manure qualifies as compost then the following conditions are met:
Also, let’s take a moment to thank the EPA and WDNR for doing such a great job indexing and making available these documents.
Edit: After going through all that, I found the composting page at extension.org which states the following:
The interesting thing is that I misread the regulations. I assumed that both a windrow (long stack of material) and vessel (big box) needed to stay above 131°F for three consecutive days and that composting in a bin also required turning. I was misinformed. Or, more accurately, I misinformed myself. Curiously, the federal standards are less rigorous than my own, personal standards.
My compost pile with the temperature around 155° F. ZOOM! say the bacteria.
*No, my recollection of a conference session is not reliable.
Do they say what counts as a vessel vs a windrow? Like, is a regular pile a vessel?
Sorry. in-vessel composting involves putting the material in a large container and managing the process very closely. more on in-vessel composting.
Man, composting is so cool.
I must agree that composting is amazing. Many of my garden buddies have had challenges with it, but my hot composting was perfect from day one. I love being lucky in gardening. It’s refreshing. My pile always heats up to 140 to 150 within 24 hours of turning and adding. My main problem now is finding vegetative browns right now. Sure I have shredded paper, napkins and dryer lint, but somehow that seems like cheating.
As for all the technical mumbo-jumbo, you can keep it. I mix an approximate equal amount of browns and greens, add air and water and presto! Then again, I have never used manure. Of course, I have no farm animals and no source for them.
Oh, and I’m partial to my free pallet bins. No clue about all that other stuff. Glad yours is heating up well!
Oh hooray! I’m glad your composts work effortlessly and well. I never had any luck with hot composting until I started using animal manure.
The technical aspects aren’t garden-driven so much as commerce-driven. One aspect of growing for market is that there are a *lot* of regulations to cleave to that are, by and by, good from a health and food safety perspective. One cannot, however, write a law that says “Manure is safe to apply when it’s been well-composted” without putting some specific, quantifiable data behind it.
My research on manure is that it’s fine after it’s been rotting for a few years, no work needed. I think rabbits are the exception. I could have sworn I read that chickens were also, because they only have one excrement and thus it’s blended carbon:nitrogen ratio was balanced. I guess that I’m mistaken there. Of course I just did my compost after mowing the lawn and had to use all the shredded news paper I could find to get a decent enough amount of browns to offset all that grass and kitchen scraps, hehe.